Craig Venter is a headline writer's dream. As brilliant as he is controversial, he was the private sector competitor who turned the official quest to sequence the human genome into a fast and furious dash to the finish. Now he has stolen a march on his rivals by announcing the first genome to be constructed in a lab.

It may sound rather trivial: his team have ingeniously rebuilt the DNA sequence of the smallest and dullest bacterium available (and let's face it, bacteria tend to be on the tiny, tedious side of things). To put it into perspective, Mycoplasma genitalium has about half a million base pairs (genetic letters), whereas Homo Sapiens have more than three billion.

Carping aside, this is an extraordinary technical feat, and another milestone in biotechnology. Scientists are beginning to understand the minimum genetic instructions that an organism can get away with. Next, they can start designing artificial entities. This success extends the boundaries of what is possible and will create a step change in genetic research.

Always the self-publicist (and no doubt with an eye to commercial investors), Venter is boosting the breakthrough for all its worth. Claims that this technique will lead to solutions to global warming, the energy crisis, and probably all other human ills are predictable. At the beginning of the century, when the first draft of the human genome was announced, Blair and Clinton made similarly grandiose claims about solving world poverty and enabling people to live forever. Given that Mycoplasma genitalium's natural home is in the male urinary tract, it would be tempting to claim that Venter is taking the piss.

There's certainly a long way to go before the potential of this technique leads to concrete social benefits. There's a huge difference between the clunky engineering that Venter's team have achieved, and the extraordinary neat and complex processes happening every second of every day in every one of our cells. Plant and animal breeders have been creating variant life forms for hundreds of years. Moreover, while a chromosome has now been spliced together for the first time, the key step is to insert it into a cell and see if this synthetic version works like the original genome of which it is a copy, in particular, whether it can reproduce itself.

Self-replication, of course, sounds alarming. It's the stuff of sci-fi nightmares: artificial organisms escape from the labs and destroy all life as we know it. Genetic engineering also raises the spectre of bioterrorism. But the truth is, everything that might be feared was feasible before today's announcement. There are already plenty of nasty organisms in laboratories around the world. For decades, it has been possible to tweak existing pathogens to create deadly new strains. Biohazard is nothing new, and this breakthrough is not a radical change from existing dangers. The same security and safety procedures are necessary with this technique as with all existing laboratories.

Perhaps the main challenge of today's news is more philosophical. Venter's work raises again the metaphysical, spiritual and moral question of what life is. Scientists can now duplicate the DNA of a living organism, albeit not a very exciting one. How, then, do we view naturally occurring DNA? What is the moral status of a genome? Because over recent months, anti-abortion critics from faith communities and beyond have been busily telling us that scientists have no business deriving stem cells from human embryonic cells, or creating hybrid embryos combining mouse and human cells. But this latest discovery suggests that DNA is not so glamorous, god given or significant. It's a complex molecular structure that can be replicated by scientists, not the meaning of life or a correlate for the soul. Perhaps we should be rather less excited and mystical about it all.

Research should progress carefully, and with appropriate safeguards and scrutiny. But we should also be careful about resorting to grandiose claims about either the wonders or the wickedness of life science.